Single-site catalyst as well as preparation method and application thereof

Abstract

The invention discloses a single-site catalyst as well as a preparation method and application thereof. According to the catalyst system, aniline with large steric hindrance is introduced to a framework of 2-phenylquinoline with high rigidity, so that better protection is provided for an active center of the catalyst system, the high temperature resistance and activity of catalyzing olefin polymerization are enhanced, and the polymerization activity at 150 DEG C can exceed 1 * 10 < 7 > g / (mol.h). The synthesis route adopted in the method is simple and easy to implement, the ligand with high yield can be obtained through one-step reaction, that is, the yield of the ligand synthesized from the 2-phenyl-8-aminoquinoline raw material exceeds 75%, and the production efficiency and the yield of the product can be improved.

Description

Technical Field

[0001] The invention relates to a single-site catalyst and a preparation method and application thereof. Background Art

[0002] Polyolefin elastomer (POE) is an elastomer polymerized by ethylene and α-olefin under the action of a homogeneous metal catalyst. It has a wide range of uses. It can be used as a rubber, a thermoplastic elastomer, and a plastic impact modifier and toughening agent. It has been well applied in the toughening and modification of a variety of plastics.

[0003] At first, polyolefin elastomers were synthesized using a high-temperature solution Insite process using a constrained geometry metallocene catalyst (CGC). This catalyst is a complex formed by a monocyclopentadiene and a transition metal of the IV subgroup by a coordination bond, which is a silane-based bridge structure that replaces a cyclopentadiene or its derivative in the bridged metallocene catalyst structure with an amino group. In addition, other catalysts currently used as polyolefin elastomer materials include binuclear constrained geometry catalysts, bridged diborane single-center catalysts, diamine ligand catalysts, and salicylaldehyde imine catalysts. Summary of the invention

[0004] In order to further enrich the selection range of catalysts for polyolefin elastomers and develop a catalyst that can maintain good catalytic activity and selectivity under high temperature conditions, the present invention is made.

[0005] As one aspect of the present invention, it relates to a single-site catalyst, which is a bidentate aminoquinoline single-site catalyst (cat-a), as shown in formula (I):

[0006]

[0007] Wherein, M is zirconium or hafnium; R1 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, fluoro or trifluoromethyl; R2 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl or phenyl.

[0008] In a specific embodiment, when catalyzing olefin polymerization at a temperature not lower than 150° C., the single-site catalyst activity is not lower than 1×10 7 g / (mol·h).

[0009] As another aspect of the present invention, it relates to a method for preparing the above-mentioned single-site catalyst, wherein the method uses 2-phenyl-8-aminoquinoline as a matrix to produce the bidentate coordinated aminoquinoline single-site catalyst.

[0010] Specifically, the method comprises the following steps:

[0011] S1. In a benzene solvent, 2-phenyl-8-aminoquinoline, bromobenzene with a substituent on the benzene ring, tri(dibenzylidene)acetone dipalladium, 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl and sodium tert-butoxide are added in sequence, the temperature is raised to reflux, and ligand L is separated by chromatography;

[0012] S2. After the ligand L in S1 undergoes a deprotonation reaction with a strong base, a metal salt is added to obtain a bidentate aminoquinoline single-site catalyst.

[0013] In a specific embodiment, in S1, the benzene solvent is selected from benzene, toluene or xylene.

[0014] In a specific embodiment, in S1, the temperature is raised to the boiling point of the benzene solvent and then refluxed.

[0015] In a specific embodiment, in S1, the ligand L is represented by formula (II):

[0016]

[0017] Wherein, R1 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, fluoro or trifluoromethyl; and R2 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl or phenyl.

[0018] In a specific embodiment, in S2, the metal salt is a chlorine-containing metal salt.

[0019] Furthermore, the chlorine-containing metal salt is selected from zirconium tetrachloride or hafnium tetrachloride.

[0020] As another aspect of the present invention, it relates to the use of the above-mentioned single-site catalyst in catalyzing olefin polymerization, wherein the single-site catalyst is used to catalyze the copolymerization reaction between ethylene and α-olefin.

[0021] In a specific embodiment, the α-olefin is selected from butene, hexene or octene.

[0022] The bidentate catalyst system of the present invention can catalyze the copolymerization of ethylene and α-olefin with high activity during high temperature polymerization (≥150° C.).

[0023] The bidentate catalyst system of the present invention introduces a large sterically hindered aniline into the highly rigid skeleton of 2-phenylquinoline, which can provide better protection for the active center of the catalyst system, enhance the high temperature resistance and activity of catalytic olefin polymerization, and the polymerization activity can exceed 1×10 7 g / (mol·h).

[0024] The synthetic route adopted in the present invention is simple and easy to operate, and a ligand with a high yield can be obtained in a one-step reaction, that is, the yield of synthesizing the ligand from the 2-phenyl-8-aminoquinoline raw material exceeds 75%, which is beneficial to improving the production efficiency and yield of the product.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the synthetic route of ligand L;

[0027] Figure 2 This is a synthetic route for bidentate aminoquinoline single-site catalysts (cat-a). DETAILED DESCRIPTION

[0028] The production of polyolefin elastomers requires a high-temperature solution polymerization process. A higher polymerization temperature is conducive to reducing the viscosity of the reaction system and ensuring better heat and mass transfer in the reactor. However, when using a high-temperature solution polymerization process to prepare polyolefin elastomers, the requirements for the catalyst are relatively high.

[0029] The inventors conducted experimental research with reference to the metallocene catalyst of Chinese Patent No. 90107395.4 and found that the catalyst has excellent polymerization activity and copolymerization ability, but its synthesis steps are complicated and the yield is low. In comparison, the synthesis steps of non-metallocene single-site catalysts are simpler.

[0030] The inventors also referred to the article on bidentate coordinated 2-methyl-8-aminoquinoline single-site catalyst reported by Philip P. Fontaine (Organometallics 2012, 31, 6244-6251; Organometallics 2015, 34, 1354-1363), which states that the catalyst catalyzes the copolymerization of ethylene and octene at 140° C. and still has good activity and copolymerization ability. However, when the inventors further explored the document, they found that the activity of the catalyst was lower when polymerized at a higher temperature (>140° C.), and the results were not as good as the inventors expected.

[0031] In view of the fact that the prior art cannot meet the inventor's expectations, the inventor made the present invention after further research and development.

[0032] On the one hand, the present invention designs a bidentate coordinated aminoquinoline single-site catalyst (cat-a), which uses highly rigid 2-phenyl-aminoquinoline as the skeleton and introduces large sterically hindered aniline to provide better protection for the active center of the catalytic system, thereby effectively enhancing the high temperature resistance and activity of catalytic olefin polymerization.

[0033] In another aspect, the present invention provides a method for preparing a bidentate aminoquinoline single-site catalyst. The inventors can obtain the ligand L with a yield of more than 75% through a one-step reaction, which can effectively improve the conversion rate and the production efficiency of the product; in addition, the process conditions in step 2 are also simple and easy to control.

[0034] On the other hand, the catalyst of the present invention can be used to catalyze the reaction of polyolefin elastomers. Under the reaction condition of 150°C, the polymerization activity of the catalyst can exceed 1×10 7 g / (mol·h).

[0035] The present invention is further described below in conjunction with specific examples, and the protection scope of the present application is not limited by the following examples. The sources of materials mainly involved in the examples are all conventional commercial products.

[0036] When designing the present invention, the inventors further optimized the intermediate ligand L for producing bidentate aminoquinoline single-site catalyst based on the prior art, see the attached Figure 1 , and make Preparation Examples 1 to 4.

[0037] Preparation Example 1 Synthesis of Ligand L1

[0038] Take a 100ml flask, add 20mmol of 2-phenyl-8-aminoquinoline, 0.8mmol of tri(dibenzylideneacetone)dipalladium, 1.6mmol of 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl and 35mmol of sodium tert-butoxide, then take 20mmol of 2,6-diisopropylbromobenzene and add 50ml of toluene. The temperature rises to 110℃, after reflux for 12 hours, stop heating, load on silica gel, prepare eluent (petroleum ether: ethyl acetate = 9:1), column chromatography, and obtain the target product: ligand L1. The detection parameters of the obtained product are:

[0039] 1 H-NMR: 8.33-8.36(s, 2H), 8.21-8.23(m, 4H), 7.75-7.76(m, 4H), 6.85(m, 1H), 6 .63-6.65(m, 2H), 4.12(s, 1H), 3.12(m, 2H), 1.33-1.35(m, 12H); Calcd.(%)for C 27 H 28N2: C: 85.22, H: 7.42, N: 7.36; found: C: 85.25, H: 7.44, N: 7.31.

[0040] Preparation Example 2 Synthesis of Ligand L2

[0041] The difference from Preparation Example 1 is that 2,6-diisopropylbromobenzene is replaced by 2,6-difluorobromobenzene. The detection parameters of the obtained product are:

[0042] 1 H-NMR: 7.99 (s, 2H), 7.68 (s, 1H), 7.28-7.39 (m, 6H), 6.55-6.73 (m, 4H), 4.16 (s, 1H); Calcd. (%) for C 21 H 14 F2N2: C: 75.89, H: 4.25, N: 8.43; found: C: 75.65, H: 4.34, N: 8.31.

[0043] Preparation Example 3 Synthesis of Ligand L3

[0044] The difference from Preparation Example 1 is that 2,6-diisopropyl bromobenzene is replaced by 2,6-diisopropyl-4-methyl-bromobenzene. The detection parameters of the obtained product are:

[0045] 1 H-NMR: 8.13-8.16(s, 2H), 8.01-8.03(m, 4H), 7.65-7.67(m, 4H), 6.63-6.65(m, 2H), 4.12(s, 1H), 3.12(m, 2H), 2.35(s, 3H), 1.33-1.35(m, 12H); Calcd.(%)for C 28 H 30 N2: C: 85.24, H: 7.66, N: 7.10; found: C: 85.35, H: 7.74, N: 6.91.

[0046] Preparation Example 4 Synthesis of Ligand L4

[0047] The difference from Preparation Example 1 is that 2,6-diisopropyl bromobenzene is replaced by 2,6-dimethyl bromobenzene. The detection parameters of the obtained product are:

[0048] 1 H-NMR: 8.01 (s, 2H), 7.67 (s, 1H), 7.28-7.39 (m, 6H), 6.45-6.74 (m, 4H), 4.17 (s, 1H), 2.38 (s, 6H); Calcd. (%) for C 23 H20 N2: C: 85.15, H: 6.21, N: 8.63; found: C: 85.25, H: 6.23, N: 8.52.

[0049] In order to clearly describe the ligand L prepared in Preparation Examples 1 to 4, its structure is described as follows, as shown in Table 1, and its yield is given:

[0050] Ligand L:

[0051]

[0052] Table 1: Ligand L structure and yield information

[0053] Ligand <![CDATA[R1]]> <![CDATA[R2]]> Yield / % L1 Isopropyl hydrogen 83％ L2 Fluorine hydrogen 81％ L3 Isopropyl methyl 79％ L4 methyl hydrogen 82％

[0054] From the data recorded in the above table, we can conclude that this type of ligand is prepared by coupling reaction, is easy to synthesize and has a high yield.

[0055] Taking the ligand L prepared in the above-mentioned Preparation Examples 1 to 4 as an example, the bidentate aminoquinoline single-site catalyst (cat-a) of the present invention is further prepared, see the attached Figure 2 , the following Examples 1 to 8 are given.

[0056] Example 1 Synthesis of Catalyst Cat-1a

[0057] Use a 50 ml Schlenk bottle to weigh the ligand L1 (2 mmol) prepared in Preparation Example 1, dissolve it in 10 mL of toluene, slowly drop 1.6 M n-butyl lithium solution (2.2 mmol) under nitrogen protection and -20°C, and react for 6 hours. Drain the toluene with a vacuum pump, wash the unreacted n-butyl lithium with n-hexane, pour out the supernatant, and obtain a yellow precipitate of lithium salt.

[0058] Take another 100ml flask, add the above lithium salt and toluene in turn, shake to dissolve, then add HfCl4 (2.5mmol) to the system, raise the temperature to 110℃ and reflux for 12 hours. After the solution cools to room temperature, filter, concentrate the filtrate to 1mL, add n-hexane to obtain a suspension, freeze overnight, filter, and filter to obtain brown-yellow crystals. The detection parameters of the obtained product are:

[0059] 1 H-NMR: 8.10-8.13 (s, 2H), 8.03-8.05 (m, 5H), 7.35-7.36 (m, 4H), 6.65-6.67 (m, 2H), 3.08 (m, 2H), 1.31-1.33 (m, 12H); Calcd. (%) for C 27 H 27Cl3HfN2: C: 48.81, H: 4.10, N: 4.22; found: C: 48.91, H: 4.24, N: 4.21.

[0060] Example 2 Synthesis of Catalyst Cat-2a

[0061] The difference from Example 1 is that the ligand L2 in Preparation Example 2 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0062] 1 H-NMR: 7.75-7.88 (m, 3H), 7.29-7.39 (m, 6H), 6.51-6.75 (m, 4H); Calcd. (%) forC 21 H 13 Cl3F2HfN2: C: 40.93, H: 2.13, N: 4.55; found: C: 40.91, H: 2.24, N: 4.61.

[0063] Example 3 Synthesis of Catalyst Cat-3a

[0064] The difference from Example 1 is that the ligand L3 in Preparation Example 3 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0065] 1 H-NMR: 7.73-7.86 (m, 3H), 7.27-7.32 (m, 6H), 6.62-6.70 (m, 3H), 3.13 (m, 2H), 2.42 (s, 3H), 1.33-1.34 (m, 12H); Calcd. (%) for C 28 H 29 Cl3HfN2: C: 49.57, H: 4.31, N: 4.13; found: C: 49.61, H: 4.27, N: 4.11.

[0066] Example 4 Synthesis of Catalyst Cat-4a

[0067] The difference from Example 1 is that the ligand L4 in Preparation Example 4 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0068] 1 H-NMR: 7.78-7.88(m, 3H), 7.32-7.38(m, 6H), 6.41-6.68(m, 4H), 2.41(s, 6H); Calcd. (%) for C 23 H 19Cl3HfN2: C: 45.42, H: 3.15, N: 4.61; found: C: 45.55, H: 3.21, N: 4.68.

[0069] Example 5 Synthesis of Catalyst Cat-5a

[0070] The difference from Example 1 is that ZrCl4 is used instead of HfCl4. The detection parameters of the obtained product are:

[0071] 1 H-NMR: 8.15-8.17(s, 2H), 8.09-8.11(m, 5H), 7.39-7.41(m, 4H), 6.68-6.71(m, 2H), 3.12(m, 2H), 1.34-1.35(m, 12H); Calcd. (%) for C 27 H 27 Cl3N2Zr: C: 56.19, H: 4.72, N: 4.85; found: C: 56.22, H: 4.74, N: 4.81.

[0072] Example 6 Synthesis of Catalyst Cat-6a

[0073] The difference from Example 5 is that the ligand L2 in Preparation Example 2 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0074] 1 H-NMR: 7.76-7.89 (m, 3H), 7.30-7.41 (m, 6H), 6.53-6.77 (m, 4H); Calcd. (%) forC 21 H 13 Cl3F2N2Zr: C: 47.69, H: 2.48, N: 5.30; found: C: 47.72, H: 2.54, N: 5.41.

[0075] Example 7 Synthesis of Catalyst Cat-7a

[0076] The difference from Example 5 is that the ligand L3 in Preparation Example 3 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0077] 1 H-NMR: 7.71-7.85 (m, 3H), 7.25-7.31 (m, 6H), 6.63-6.71 (m, 3H), 3.15 (m, 2H), 2.41 (s, 3H), 1.31-1.32 (m, 12H); Calcd. (%) for C 28 H 29Cl3N2Zr: C: 56.89, H: 4.94, N: 4.74; found: C: 56.72, H: 4.84, N: 4.81.

[0078] Example 8 Synthesis of Catalyst Cat-8a

[0079] The difference from Example 5 is that the ligand L4 in Preparation Example 4 is used to replace the ligand L1 in Preparation Example 1. The detection parameters of the obtained product are:

[0080] 1 H-NMR: 7.78-7.88(m, 3H), 7.32-7.38(m, 6H), 6.41-6.68(m, 4H), 2.41(s, 6H); Calcd. (%) for C 23 H 19 Cl3N2Zr: C: 53.02, H: 3.68, N: 5.38; found: C: 53.11, H: 3.74, N: 5.45.

[0081] In order to clearly describe the bidentate aminoquinoline single-site catalyst cat-a prepared in Examples 1 to 8, its structure is described as follows, as shown in Table 2, and its yield is given:

[0082] Catalyst cat-a:

[0083]

[0084] Table 2: Catalyst structure information and yield table

[0085] catalyst M <![CDATA[R1]]> <![CDATA[R2]]> Yield / % Cat-1a Hf Isopropyl Hydrogen 71％ Cat-2a Hf Fluorine Hydrogen 73％ Cat-3a Hf Isopropyl methyl 72％ Cat-4a Hf methyl Hydrogen 76％ Cat-5a Zr Isopropyl Hydrogen 75％ Cat-6a Zr Fluorine Hydrogen 69％ Cat-7a Zr Isopropyl methyl 67％ Cat-8a Zr methyl Hydrogen 65％

[0086] According to the experimental data recorded in the above table, the synthesis route of this type of catalyst is simple and has a high yield, which can effectively reduce the production cost of the catalyst.

[0087] The inventors applied the above-mentioned Examples 1 to 8 to the reaction of catalyzing olefin polymerization, and obtained the following Application Examples 1 to 11.

[0088] Application Example 1

[0089] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-1a prepared in Example 1, which specifically comprises the following steps:

[0090] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtering. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0091] The catalytic activity of cat-1a in this application example is 7.1×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 225 kg / mol, the molecular weight distribution index is 2.1, the glass transition temperature is -55°C, and the melting temperature is 61°C.

[0092] Application Example 2

[0093] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-2a prepared in Example 2, which specifically comprises the following steps:

[0094] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtering. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0095] The catalytic activity of cat-2a in this application example is 1.5×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 161 kg / mol, the molecular weight distribution index is 2.3, the glass transition temperature is -45°C, and the melting temperature is 85°C.

[0096] Application Example 3

[0097] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-3a prepared in Example 3, which specifically comprises the following steps:

[0098] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtering. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0099] The catalytic activity of cat-3a in this example is 6.2×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 195 kg / mol, the molecular weight distribution index is 2.3, the glass transition temperature is -47°C, and the melting temperature is 75°C.

[0100] Application Example 4

[0101] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-4a prepared in Example 4, which specifically comprises the following steps:

[0102] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtering. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0103] The catalytic activity of cat-4a in this application example is 4.6×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 171 kg / mol, the molecular weight distribution index is 2.5, the glass transition temperature is -45°C, and the melting temperature is 80°C.

[0104] Application Example 5

[0105] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-5a prepared in Example 5, which specifically comprises the following steps:

[0106] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Zr:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0107] The catalytic activity of cat-5a in this application example is 6.5×10 7 g / (mol Zr·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 151 kg / mol, the molecular weight distribution index is 2.3, the glass transition temperature is -44°C, and the melting temperature is 73°C.

[0108] Application Example 6

[0109] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-6a prepared in Example 6, which specifically comprises the following steps:

[0110] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Zr:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0111] The catalytic activity of cat-6a in this application example is 1.3×10 7 g / (mol Zr·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 144 kg / mol, the molecular weight distribution index is 2.3, the glass transition temperature is -41°C, and the melting temperature is 77°C.

[0112] Application Example 7

[0113] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-7a prepared in Example 7, which specifically comprises the following steps:

[0114] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Zr:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0115] The catalytic activity of cat-7a in this application example is 4.4×10 7 g / (mol Zr·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 144 kg / mol, the molecular weight distribution index is 2.1, the glass transition temperature is -50°C, and the melting temperature is 68°C.

[0116] Application Example 8

[0117] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-8a prepared in Example 8, which specifically comprises the following steps:

[0118] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Zr:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0119] The catalytic activity of cat-8a in this application example is 3.2×10 7 g / (mol Zr·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 143 kg / mol, the molecular weight distribution index is 2.4, the glass transition temperature is -44°C, and the melting temperature is 76°C.

[0120] Application Example 9

[0121] This application example provides a method for catalyzing the copolymerization of ethylene and hexene using the catalyst cat-1a prepared in Example 1, which specifically comprises the following steps:

[0122] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-hexene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-hexene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-hexene copolymer.

[0123] The catalytic activity of cat-1a in this application example is 6.5×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-hexene copolymer is 138 kg / mol, the molecular weight distribution index is 2.3, the glass transition temperature is -41°C, and the melting temperature is 86°C.

[0124] Application Example 10

[0125] This application example provides a method for catalyzing the copolymerization of ethylene and butene using the catalyst cat-1a prepared in Example 1, which specifically comprises the following steps:

[0126] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-butene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 150°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-butene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and dried in vacuo at 70°C for 12 h to obtain ethylene-butene copolymer.

[0127] The catalytic activity of cat-1a in this application example is 6.9×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-butene copolymer is 141 kg / mol, the molecular weight distribution index is 2.4, the glass transition temperature is -40°C, and the melting temperature is 95°C.

[0128] Application Example 11

[0129] This application example provides a method for catalyzing the copolymerization of ethylene and octene using the catalyst cat-1a prepared in Example 1, which specifically comprises the following steps:

[0130] Under anhydrous and oxygen-free conditions, 1000 mL of toluene, 300 mL of 1-octene, and 1000 μmol of methylaluminoxane (Hf:Al=1:500) were added into the reactor, the temperature was raised to 170°C, 2 μmol of catalyst cat-1a was dissolved in 10 mL of toluene and then pressed into the reactor with ethylene, the ethylene pressure was adjusted to 2 MPa, and the copolymerization of ethylene and 1-octene was carried out at 150°C for 30 min. After the reaction stopped, the polymerization was terminated by acidifying ethanol with 5% hydrochloric acid, stirring for 0.5 hour, and then filtered. The filtrate was washed three times with ethanol and vacuum dried at 70°C for 12 h to obtain ethylene-octene copolymer.

[0131] The catalytic activity of cat-1a in this application example is 7.0×10 7 g / (mol Hf·h), the weight average molecular weight of the prepared ethylene-octene copolymer is 228 kg / mol, the molecular weight distribution index is 2.2, the glass transition temperature is -54°C, and the melting temperature is 60°C.

[0132] Combining Examples 1 to 8 and Application Examples 1 to 11, we can find that the catalysts prepared in Examples 1 to 8 have a yield of no less than 65%, and still have excellent catalytic activity under high temperature reaction conditions of 150°C. Among them, taking Example 1 and the corresponding Application Example 1 as an example, the catalyst yield prepared therefrom is as high as 71%, and the catalytic activity at 150°C is as high as 7.1×10 7 g / (mol Hf·h).

[0133] In addition, in combination with Application Examples 1 and 9 to 11, we can also find that when the bidentate aminoquinoline single-site catalyst prepared by the present invention is used to catalyze the copolymerization of ethylene and α-olefins, the catalyst can still maintain a high catalytic activity at 150°C, and the catalytic activity is not less than 6.5×10 7 g / (mol·h), and even at 170°C, its catalytic activity can reach 7.0×10 7 g / (mol·h). From this, we can infer that the bidentate aminoquinoline single-site catalyst prepared in the present invention has strong high temperature resistance, and the high temperature resistance condition of the catalyst is not less than 170°C.

[0134] Application Comparative Example 1

[0135] The bidentate coordinated 2-methyl-8-aminoquinoline single-site catalyst reported by Philip P. Fontaine (Organometallics 2012, 31, 6244-6251; Organometallics 2015, 34, 1354-1363) was used as a comparative example.

[0136] By comparing the two, we found that when the bidentate coordinated 2-methyl-8-aminoquinoline single-site catalyst is applied to olefin polymerization, the polymerization temperature of the catalyst in the reference document is lower than that of the catalyst of the present invention.

[0137] In summary, the bidentate catalyst system of the present invention can not only enhance the high temperature resistance and activity of catalytic olefin polymerization, but also can catalyze the copolymerization of ethylene and α-olefins with high activity at high temperature (≥150°C), and the polymerization activity of the catalyst at 150°C can exceed 1×10 7 g / (mol·h). In addition, the synthetic route adopted in the present invention is simple and easy to operate, and a ligand with a high yield can be obtained by a one-step reaction, that is, the yield of synthesizing the ligand from the 2-phenyl-8-aminoquinoline raw material exceeds 75%; and then the bidentate coordinated aminoquinoline single-center catalyst (cat-a) is prepared from the intermediate ligand L, and its yield is not less than 65%. Based on this, when it is mass-produced in industry, the production cost can be effectively saved.

[0138] The above are only preferred feasible embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Various modifications or applications made according to the above embodiments are within the protection scope of this technical solution.

[0139] Although the specific embodiments of the present invention have been described in detail, it will be understood by those skilled in the art. According to all the teachings disclosed, various modifications and replacements can be made to those details, and these changes are all within the protection scope of the present invention. The full scope of the present invention is given by the attached claims and any equivalents thereof.

Claims

1. A single-site catalyst, characterized in that The single-site catalyst is a bidentate aminoquinoline single-site catalyst, as shown in formula (I): Wherein, M is zirconium or hafnium; R1 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, fluoro or trifluoromethyl; R2 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl or phenyl.

2. The single-site catalyst according to claim 1, characterized in that When catalyzing olefin polymerization at a temperature not lower than 150°C, the catalytic activity of the single-site catalyst is not lower than 1×10 7 g / (mol·h).

3. A method for preparing the single-site catalyst as claimed in claim 1, characterized in that: The method uses 2-phenyl-8-aminoquinoline as a matrix to produce the bidentate coordinated aminoquinoline single-center catalyst.

4. The method for preparing a single-site catalyst according to claim 3, characterized in that: The method comprises the following steps: S1. In a benzene solvent, 2-phenyl-8-aminoquinoline, bromobenzene with a substituent on the benzene ring, tri(dibenzylidene)acetone dipalladium, 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl and sodium tert-butoxide are added in sequence, the temperature is raised to reflux, and ligand L is separated by chromatography; S2. After the ligand L in S1 undergoes a deprotonation reaction with a strong base, a metal salt is added to obtain a bidentate aminoquinoline single-site catalyst.

5. The method for preparing a single-site catalyst according to claim 4, characterized in that: In S1, the benzene solvent is selected from benzene, toluene or xylene.

6. The method for preparing a single-site catalyst according to claim 4, characterized in that: In S1, the temperature is raised to the boiling point of the benzene solvent and then refluxed.

7. The method for preparing a single-site catalyst according to claim 4, characterized in that: In S1, the ligand L is represented by formula (II): Wherein, R1 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, fluoro or trifluoromethyl; and R2 is selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl or phenyl.

8. The method for preparing a single-site catalyst according to claim 4, characterized in that: In S2, the metal salt is a chlorine-containing metal salt.

9. The method for preparing a single-site catalyst according to claim 8, characterized in that: The chlorine-containing metal salt is selected from zirconium tetrachloride or hafnium tetrachloride.

10. Use of the single-site catalyst according to any one of claims 1 to 9 in catalyzing olefin polymerization, characterized in that: The single-site catalyst is used for catalyzing the copolymerization reaction between ethylene and α-olefin.

11. Use of the single-site catalyst according to claim 10 in catalytic olefin polymerization, characterized in that: The α-olefin is selected from butene, hexene or octene.

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